For purposes of illustration, reference will be made to the use of the present invention with respect to the casting of engine cylinder heads. It should be understood by those of ordinary skill in the art that the invention is not limited to use in casting engine cylinder heads and can be used in casting other products.
In a semi-permanent molding (SPM) process for casting of an aluminum internal combustion engine cylinder head, a metal die and an expendable core package are used. Unlike a sand mold in a sand casting process, the die can be used repeatedly to produce several castings. The die is adapted to permit rapid removal of the casting from the die and efficient positioning of a new core package. Typically, a coating or wash is applied to the die to mitigate against an adhesion of the casting thereto. The coating can by any conventional material such as an insulating material and a lubricious material, for example. The core package is disposed in the die to define internal and external surfaces of the engine cylinder head such as the intake and exhaust ports, water jacket, cam openings, and oil galleries, for example. The core package is formed by stacking a plurality of separate cores. Contrary to the permanent mold process (PM) which uses metal cores, the SPM process uses resin-bonded sand cores. Typically, the sand cores are formed by blowing resin-coated foundry sand into a core box and curing the sand therein.
Traditionally, the core package is disposed in the die by one of a manual process and an automatic process. The manual process involves assembling the core package within the die or outside of the die by an operator. The core package assembled outside of the die must then be transferred by the operator to the die and disposed therein.
In the automatic process, a fixture is typically used having a plurality of posts depending therefrom adapted to transfer the core package to the die and dispose the core package within the die. The posts include a plurality of balloon-like bladders adapted to be received in a plurality of apertures formed in the cores of the core package. In operation, the bladders are disposed in the apertures and caused to inflate, securing the fixture to the core package. Once the core package is disposed in the die, the bladders are caused to deflate and release the core package from the fixture. A problem with such a process is it is not feasible to form apertures for receiving the bladders in smaller and more complex cores.
It would be desirable to produce a mold assembly device capable of transferring a core package to a die and disposing the core package in the die, wherein the core package includes cores of varying sizes and complexity.